Scientists say increasingly severe wildfires, such as those seen in California this month, could contribute significantly to global carbon emissions, according to BBC News. Current commitments from countries are already not enough to meet Paris agreement targets, and worsening wildfires are a factor that hasn’t been properly accounted for.
“We can’t neglect the emissions from wildfires,” said Ramon Vallejo, a fire ecology scientist at the University of Barcelona. “Particularly now that we are seeing intense wildfires all around the world.”
Scientists generally estimate that wildfires currently generate about 20 percent of total greenhouse gas emissions, and that total is expected to rise to 30 percent by 2100.
In addition to the emissions generated by the fires themselves, wildfires also eliminate forests, which absorb carbon dioxide.
One study this year suggested emissions from wildfires have actually decreased over the past 80 years, due to the conversion of forest and savannah into farmland. But the decrease was minor, due to the increasing size and severity of the fires, which could further increase with climate change.
While the level of carbon emissions from recent wildfires in California is still uncertain, some estimates have projected that one wildfire last year emitted as much carbon in a week as all automobiles emitted in the state over a full year.
California is not the only part of the world that has seen increasingly intense wildfires. This year has been the worst wildfire season in Europe since 1900, with 91 people killed in Greece and 70 people in Portugal and Spain. Sweden also saw severe wildfires that burned 30,000 hectares of forest. In Indonesia, a 2016 wildfire released more carbon dioxide each day than all of Europe’s daily fossil fuel use.
One study found that boreal forests are burning faster than at anytime in the last 10,000 years. Another recent study, published in Nature Communications, found a three-degree Celsius temperature increase would lead to a 100 percent increase in wildfires in the Mediterranean. Even a 1.5-degree increase, as aimed for in the Paris agreement, would see a 40 percent increase.
Lead author of the report, Dr. Marcus Turco, said that “the projection is that most places across the globe will see similar intensified wildfires in a warming climate.”
Some researchers say emissions from wildfires are probably minor compared to other sources, but warn that fires in peatlands are the real danger.
“The real wildcard is permafrost thaw due to climate change that can make a large amount of northern peat susceptible to fire, which was previously unavailable for burning,” says Canadian Forest Service researcher Bill Degroot.
The Indonesian peat fire of 1997 to 1998 is thought to be the highest emissions from a wildfire in modern times, with estimates as high as 3.7 billion metric tons of carbon dioxide.